This invention relates to a communication path control device and communication path control method, and communication path control unit for data distribution service from a network using the telephone line and broadcast line.
The analog telephone line and digital telephone line such as ISDN are usually used as the line for between home computers and the external network. However, the data transmission rate of the public data network ranges around as low as 30 kbps for analog telephone line used through a modem, and is as low as 64 kbps or 128 kbps for the digital line such as ISDN. Hence, it takes a long time of several minutes to several ten minutes to transmit large volume data of an image after access (dial-up connection) to an external network through a public line. In particular, various service supplied from the Internet often contain images and the desired information cannot be down-loaded in a short time, such slow transmission can result in reduced efficiency and attractiveness. Therefore, it is desirable to use a large capacity line in order to transmit large volume data at a high rate between a computer and external network such as Internet.
The privately used digital line, CATV (wired television) line using a co-axial cable, and satellite broadcast line are available as large volume line usable for data transmission between computers and external networks.
The privately used digital line is a high rate digital line installed separately from the public line network, and is a line which a user who has a private contract with a communication provider can use exclusively. Recently, some home communication users use privately used digital lines for connecting to the Internet.
The CATV line is a line used for transmission of broadcast programs installed between home users and a broadcast provider. The line comprises usually a co-axial cable which is a capable of two-way data communication, in some cases two-way communication is carried out between a program distributor side and a receiving side using one co-axial cable.
On the other hand, the satellite broadcast line is a one-way line for distributing broadcast programs from one broadcasting satellite to a multitude of users. Therefore, in the case that the satellite broadcast line is used as communication path for transmitting/receiving data between computers and an external network, it is required to also use a terrestrial two-way line such as public line or privately used line. It is therefore difficult to connect an arbitrary computer to a satellite line through a public line.
A receiving device for receiving the data transmitted from a satellite line to a computer is structured generally so as to be connected to a specific type of computer using a privately used line.
Further, in the case that computers constitute a network such as a LAN (Local Area Network), it is usual that a computer is connected to an external network through a path control device called a router which is used for controlling an access path between the network.
In the case that a plurality of access paths are available between a computer and an external network, the router is provided with a function to select a path out of the plurality of access paths based on, for example, the address of the data. However, a conventional router is not provided with a function to control the return path of a return data from the external network to the data transmitted from an arbitrary computer.
As described herein above, in the case that data are transmitted/received through a plurality of communication apparatus or communication paths, a communication path control means is required to control the communication path. However, conventional communication path control means is poor in flexibility because such a communication path control means is structured usually using a computer.
In the case of broadcast data transmitted from a satellite line, a user other than specific user who has a reception contract can easily receive it. Therefore, the above-mentioned receiving device should have a function for scrambling so that a specific user can receive the data correctly and a user who does not have a reception contract can not receive it.
The present invention was accomplished in view of the above-mentioned problems. It is the object of the present invention to provide a communication path control device and communication path control method provided with a function to control the communication path of data between networks and additionally data reception function from a satellite line.
The communication path control device of the present invention proposed to solve the above-mentioned problem is a communication path control device for controlling communication paths between the first network and second network provided with the first interface section for connecting to the first network, the second interface section for connecting to the first communication path for two-way data transferring between the second network, the third interface section for connecting to the second communication path having a transmission capacity larger than the first communication path for one-way data transmission from the second network to the first network, and a control means for selecting any one of the first communication path and second communication path as the return path of the reply data responsive to the transmitted data based on the data transmitted from the first network to the second network through the first communication path.
The communication path control method of the present invention proposed to solve the above-mentioned problem is a communication path control method for controlling communication paths between the first network and second network comprising the first transfer step for transferring the data inputted from the first network through the first interface section to the second interface section, the second transfer step for transferring the data from the second interface section to the first communication path served for two-way data transmission between the second network, and the third transfer step for outputting the reply data responsive to the data addressing to the third interface section from the second communication path for one-way transmitting the data from the second network to the first network having a transmission capacity larger than the first communication path, wherein the return path of the reply data responsive to the transmitted data is specified based on the data transmitted from the first network to the second network through the first communication path.
According to the communication path control device and method, the path of the reply data responsive to the data transmitted from an arbitrary computer to a network is controlled, therefore, in the case that a large capacity data is down loaded, a large capacity one-way line is designated for short time data transfer, thus the network is operated efficiently.
The communication path control unit of the present invention proposed to solve the above-mentioned problem is a communication path control unit for controlling communication paths between a local area network and the Internet provided with the first interface section having the first connection section for connecting to the local area network, the second interface section having the second connection section for connecting to the first communication path for two-way data transmission between the Internet, the third interface section having the third connection section for connecting to the second communication path for one-way data transmission from the Internet to the local area network, a reception means for receiving the satellite broadcast data inputted to the third interface section, a control information memory means for storing the previously set relationship between the address information of the local area network and port number information, and the address information of the Internet and port number information, and a control means for selecting any one of the first communication path and the second communication path as the return path of the reply data responsive to the transmitted data based on the data transmitted from the local area network to the Internet through the first communication path.
According to the communication path control unit of the present invention, the plurality of interface sections such as the interface section for satellite lines provided with the data reception function from satellite lines, interface section for a LAN, and interface section for telephone lines, and the communication path control function for selecting a communication path between them based on the transmitted data are contained in a compact box, and further line connection terminals of the respective interfaces are structured on the box panel using universal connectors and thereby, the communication path control unit of the present invention is served as a communication path control device for various computers regardless of the type of a computer.